The present invention relates to exercise devices for developing and conditioning various muscles in the human body, and more particularly to exercise devices for aerobic conditioning in which exercise is obtained by exerting force against a resistant element.
There has been a growing awareness in recent years that physical exercise is important to mental and physical health and fitness. It is now generally believed that a conditioning program should entail exercise of a wide variety of muscles of the body and should also condition the heart and lungs, i.e., provide aerobic benefits.
An important part of some comprehensive exercise programs involves weight training which generally calls for specialized equipment. Barbells with removable weights comprise a simple and relatively inexpensive means for exercising some muscles. However, barbells are severely limited in the groups of muscles which can be strengthened or conditioned by their use. As a result of the limitations of the use of barbells alone in physical training, weight training devices have been developed which can provide many more exercises than can be obtained merely through the use of barbells. These devices generally provide resistance to an exerted force by means of weight and pulley arrangements, or by means of resilient elements such as springs or elastomeric elements such as elastic cords.
Apparatus which uses weights have certain disadvantages. First, it is necessary to have a large number of different weights available. Secondly, the addition or removal of weight is a potential source of accident. A further disadvantage lies in pulley and cable arrangements typically used which add to the weight and complexity of the apparatus and which is a potential cause of malfunctioning.
Resilient force-resisting elements, such as elastic cords, are light, easy to store, and provide a wide range of resisting forces. However, elastic elements are difficult to attach to exercise apparatus if it is necessary to stretch them to put them in place. As a result, in typical exercise apparatus, the elastic elements are placed in the apparatus under conditions where no tension is applied. However, this results in a dead spot where there is no resistance at the beginning of an exercise movement.
Many exercise devices, whether using weights or resilient force-resisting elements, are either large, expensive machines which are not practical for home use, or are specialized devices which either are capable of exercising only limited areas of the body or require difficult or time-consuming adjustments to afford a wide range of exercises for the user. It is generally believed that in order to achieve aerobic benefits in using exercise equipment, a series of exercises should be carried out within a relatively short time span, and no more than about 45 to 60 seconds should be allowed between exercises. This requires the capability of quickly and easily changing the apparatus from one set-up to another.